We request funding for the acquisition of equipment needed for the 3-dimensional (3-D) reconstruction and analysis of biological structures. The major equipment items are a laser-scanning confocal microscope (Zeiss LSM) and a high-performance 3-D graphics workstation (Silicon Graphics IRIS VGX series). These will be part of an integrated effort in biological imaging, which will involve 14 research labs in the Biology Division at Caltech. One set of projects will utilize the confocal system for studying single cells, early embryos, and other structures at the microscopic level. Another set of projects will be aimed at generating 3-D reconstructions of macroscopic structures, including the brains of monkeys, humans, and other species. For many of these projects, we will be able to use commercially available software for image analysis and 3-D reconstruction. We also intend to develop software for specialized applications, but this activity will not be directly supported by the requested funding. To promote and coordinate these efforts, we have established a Biological Imaging Center on campus. This will be a professionally staffed facility, and we anticipate that it will substantially enhance the efficiency, ease, and flexibility with which the requested equipment will be used.